An innovative method of in vivo imaging for detection and pathophysiological classification of relatively superficial malignancies is proposed. The technique, sono-contrast induced functional imaging and spectroscopy (SCIFIS), builds upon existing diffuse reflectance spectroscopy (DRS) in the near infrared region but uses standing wave focused ultrasound deposition as a contrast agent to improve the sensitivity and specificity of DRS. The overall goal is to develop a non-invasive, real-time modality for cancer diagnosis, prognosis and post-treatment surveillance. The basis of the proposed in vivo imaging method is that acoustic radiation force delivered by focused ultrasound forming a standing wave causes reversible compression of the vasculature and/or blood flow stasis, and thus temporal changes in hemoglobin concentration, which are registered in the dynamic (pre- and post-insonification) observation of near-infrared spectra. By intersecting the optical path and the acoustic path at an angle and subtracting measured spectra pre- and post-deposition of sono-contrast, signatures of vascular pathophysiology can be identified at the intersecting location. In the R21 phase, C3H mice inoculated with murine mammary tumors on the left legs will undergo in vivo SCIFIS measurement prior to immunohistochemical examination. Principal component analysis neural networks (PCANN) will be used in data analysis/correlation, leading to definitively tests of the underlying hypotheses via receiver operating characteristics analysis and statistical correlation of tumor detection and vascular distribution predictions. In the R33 phase, clinical evaluation of the SCIFIS technique will commence following system optimization by Monte Carlo simulation. Non-invasive, in vivo acquisition of SCIFIS spectra will be collected in patients undergoing biopsy for suspicion of breast cancers. The predictive model based on PCANN will be quantitatively compared with pathological tissue diagnoses. In addition, response to radiation treatment and outcome will be correlated with angiogenesis and/or tumor hypoxia findings in the sonocontrast spectra for those patients who are found to have malignant diagnoses and eventually receive radiotherapy.